BF₃·Et₂O mediated one-step synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines

Abstract

A simple and efficient one-pot synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines by a BF·EtO mediated novel methodology, from easily available α,β-unsaturated ketones/arylidene ketones, phenyl acetylenes and substituted nitriles, has been described. This novel annulation provides quick access to complex polycyclic frameworks with an excellent substrate scope.

Recent advances in the transition metal-free synthesis of heterocycles from α,β-unsaturated ketones

“…The one pot annulation strategy provides access to both pyridines and isoquinoline derivatives 67 . 37 We have used easily accessible substrates such as arylidene ketones 64 for the one pot reaction. Operational simplicity, short reaction time and dual role of nitrile as solvent as well as nitrogen source are the merits of this transition metal free reaction.…”

Electrophilic Thiocyanato Reagent Assisted Oxa-Michael/Thiocyanation of α,β-Unsaturated Ketones

“…Substrates 1a and 1b are commercially available. Substrates 1c – 1k , , 3a , 3b and 3c , 3d and 3e , 3f , 3g – 3q and 3s and 8 , , and 5a and 5b are known compounds and prepared according to known procedures.…”

BF3·OEt2-Mediated Tandem Annulation: A Strategy To Construct Functionalized Chromeno- and Pyrano-Fused Pyridines

“…Owing to the aforementioned biological importance of pyridines, related hybrids, and our interest in the design and development of medicinally essential heterocycles, recently we have unraveled a one-pot multicomponent cascade synthesis of pyridine appended heterocycles from the readily accessible arylidenones, alkynes, and nitriles . This simple protocol has led us now to report the diverse library of chromeno­[3,4- c ]­pyridines, thiochromeno­[3,4- c ]­pyridines, pyrano­[3,4- c ]­pyridines, and thiopyrano­[3,4- c ]­pyridines.…”